Automatic stop for whip-hoists.



No. 826,529. I PATENTBD JULY 24, 1906.

w. n. BALDWIN a; J. n. IHLDBR. AUTGMATIG STOP FOB WHIP Hams.

APPLIOATIOI I-ILIJD MAB. BL 1904.

2 SHEETS-SHEET I.

46 a 4 y 021 f2 13% "B14 coo e a for electric whiphoists;

of New Yor .as might occur from overwin ing.

in contact with a" rake-strap vided withffictioir-surfaees which areadept- UNITED STATES PATE OFFICE.-

WiLLrAM D. BALDWIN, OF saw roan, AlZD J WHN D. IHLDER, F YONKERS.: NEWYORK, sss'rososs TO oris ELEVATOR cou- PANY, or EAST ORANGE, NEW JERSEY,A cosrossrros to]? NEW JERSEY.

Specification of Letters Patent.

Patented July. 24, 1906.

a emi filed m r emcee. Serial 1n. male-i.

To all whom it may concern:

Be it known that we, WxLLmn i). BALD- wm, residin at New York city, inthe county and JOHN Illnansn, residing at Yonkers, in the county ofWestchester State of New York, citizens of 'the'United States, haveinvented certain new and useful Im rovements in Automatic Steps forVVhip- Holsts, of which the following is a specification.

Our invention relates to automatic stops and its object is to preventsuch machines from carrying their ends beyond the rop'er limits oftravel and to provide means or avoidin such accidents We willdescribe awhip-hoist comprising our invention and point out the novel featuresthereof in claims.

Referri to'the drawings, ure 1 is B. side elevation of a whi -hoist, sowing the mechanical features of'the present invention. Fig. 2 is awiring diagram, showing the electrical connections of a whip-hoistembodying our invention. is a diagram of a part of the apparatus 5 ownin Fig. 2, but with its circuitssomewhat changed to showa modificationof the invention. 7

Like figures of reference indicate cor-re spond' parts in the variousfigures. V

a 50 designates an electric motor, to the sh aft of which is securelyattached a. frietion pfii w This pinion is adapted to coast with afriction-sheave .52. A winding-drum or Windlass is attached to a shaft54, to which the fiictien sheave 52 is also attached. The shaft 54 is anported on an eccentric 55, which may he iiirned by means ot fsi lever 55to raise or lower the hiction-wheei'sz The outei eriphery of thefrictioQ- whscLSQ is smootli and is ads ted whenr isejd som 59." 'iheinside of the of the friction-wheel 52 is proed when the sheave islowered to coast with the friction-pinion 51, so that the sheave 52, andconsequently the drum 53, will be driven bii the pinion when the latteris rotating.

e lever 56 may becexaperated directly by hand or may be opera from adistance by with a stop safi 117 near its so means of a rope 58connectedto it; A weight 57 may be attached .tothe lever-56tillfacilitate the operation of the apparatus.

desi notes a starting-controller for. the motor. t is of awell-known'type. ltcom prises a hand-lever 21, which is connected to oneof the mains from a source of electrical supply, in this case thepositive main, whichis es' lgnated b w in tho-drawmgsi This hand-leveris lield in the position shown against a stop 26 by means of a spring25. When it is desired to start the motor, the hand le vsrm is moved tothe right. It then establishesa circuit through the contacts 22, theresistance-coils 23, the series field 11, and the armature 10 of themotor-to the negative main. The shunt-field 12 of the motor, as hereshown, is connected directly across the mains. As the hand-lever 21 ismoved forther to the right it cuts out the starting resistance 23 step bstep until it reaches the lastocontact 22,wlien it is all cut out. Thehand-leverfalso establishes another circuit through a'holding-magnet 24,the coilof an auxiliary magnet a limit-switch to the negative mam. 'lean electric current flows through this circuit it one izes thetwo'inagnets in it. The first of t ese (the hflidl -magnet 24) holds thelever 21 over to the rig t against the action of the spring 25. Theauxiliary magnet 30 separates its contests 32 33 and breaks what wouldotherwise he a short circuit across the motor-armature through a.resistance 60. This short circuit is shown in the dra by a broken linemade up of dots and d es. After the motor has" been started, as has justbeen deseriseirgit continue to rotate as long as its circuits are notinterrupted. Thiswill part motion to the friction-pinion 51, and theapparatus may be used for raising and lowering packages at The rogercable 46, which is used to connect pac ges to the drum. 53 is rovided roe is run through or near an arm 44 01- the limitswitches ,and'is'soarranged that it passes the arm iifreehuhut that the stop-balls? willengages-1 and the letter if it The arm 44 is pivoted at 45. Its otherend 43 forms the movable blade of an electric switch and normally gized.

will no-longer be driven by the current.

touches the stationary contacts 41 42 and completes the circuit throughthe holding m et 24 and theauxiliary magnet-coil 31.

enever the stop-ball 47 engages the arm 44, as it will whenever itapproaches the upper limit of its travel, it will push the latter up andthe switch-blade 43 down, thus breaking the circuit between the contacts41 and 42. This will interrupt the flow of current through theholding-ma et 24 and the auxiliary ma et 30, and t ey will be dener- T ehand 9 lever 21 will now be thrown back against the etc 26 by the spring25. This will cut off t e supply of current from the mains to thearmature and series fields of the motor, so that the molthor e contacts32 33 of the auxiliary magnet 30 will come to ether, thus closing ashort circuit across t e armature 10 through the resistance 60. Thecurrent generated by the rotation of the armature flowing through thisshort circuit will act as a brake and tend to stop the motor and bringthe apparatus to rest.

We will now describe the modification illustrated in Fi 3. In this casethe auxiliar magnet 30 as the same contacts32 33 an the same coil 31 asbefore, but it has another coil 34 added, which is in the circuitcontaining the resistance 60 and which when the contacts 32 33 are toether short-circuits the motor-armature. T e coil 34 is arran ed tocounteract the effect of coil 31, so t at when both coils are excitedthe magnet 30 will not be energized and its contacts 32 33 will remaintogether. The object and pur ose of this arrangement is to pi revent thelbad descending -too rapidly. his might happen if after the motor hadstop ed, as above described, the load should escend and the limit-switch40 should close again, for then the load would drive the motor and thecurrent generated by the motor-armature would energize the auxiliarymagnet 30 and cause the latterto break at 32 33 the armature shortcircuit. This would allow .the motor to rotate freely and the load torun down with but little retardation and with a possibility of injurinitself when it strikes ottom. This troub e can be overcome by arrangingthe auxiliary switch 40 to remain open after it has been opened by thestopball 47 until it is closed by hand but as this switch is often inaninaccessible place we sometimes use a switch which closes itself as soonas the stop-ball moves away from it. In such a case i the load is heavyenough to drive the motor the latter will energize the armature shortcircuit and allow the load to run down freely; butthe coil 34, which isin the armature short circuit, is added to the magnet 30 to neutralizethe efl'ect of the coil 31, so that the ma et 39 will not break theshort circuit w e the motor is generating current. Thus the load willrun down slowly retarded by the braking effect of the short circuit onthe armature, and will be protected from injuries due to its too rapiddescent. The coil 34 will not prevent the magnet 30 from becomingenergized by the coil 31 when the motor is started up, because the coil31 receives its full current strength as soon as the hand-lever 21touches the first stationary contact 22, and at that time the coil 34 isshort-circuited by the motor-armature. The auxiliary magnet will at onceseparate its contacts 32 33 and break the circurt to the coil 34.

Havingrdescribed our invention, what we claim is 1. The combination witha whip hoist driven by an electric motor, of a source of electricalsupply, a 1:0 to connect a load to the hoist, a switch in t e path ofthe ro e and arranged to be opened by the latter w en its end approachesthe limit of its travel, said switch controlling the circuit of aholdingmagnet which when broken cuts oil the electrical supply from themotor, also controllin the circuit of an auxiliary magnet which whenbroken establishes a short circuit through resistance across themotor-armature.

2. The combination with a whip hoist comprising a motor, astarting-rheostat, a drum, gearing connecting the motor and the drum,and a rope to connect a load to the drum, of a source of electricalsupply, a switch in the ath of the rope and arranged to be opened y theletter when its end up proaches the limit of its travel, said switchcontrolling the circuit of a holding-m which when broken cuts off theelectrical supply from the motor, also controlling the circuit of anauxiliary magnet which when broken establishes a short circuit throughresistance across the motor-armature 3. The combination with a whiphoist comprising a motor, a starting-rheos'talt, a drum, gearingconnecting the motor and the drum, and a rope coactin with the drum andhaving a sto -ball attac d near one end, of a source of e ectrical suppla switch in the path of the rope, arran to be :opened by the stop-ballon the to said switch controlling'the circuit of a l'idlding-magneltwhich when broken cuts oil the electrical supply from the motor, alsocontrolling the circuit of an auxiliary magnet which whenbroken-establishes a short circuit though resistance across themotor-armature.

4. The combination of a whip hoist, driven by an electric motor, of asource 0! electrical supply, a rope to connect a load tc the 'hoist, aswitch in the path :of the rep! and arranged to be 0 sued by the latterwlicq its end approaches te limit of its travel, air switch controllingthe circuit of a ho r magnet which when broken cuts oil the triealsupply from the motor, also eontrbl- In testimony whereof we have signedour ling the circuit of a coil on an auxiliary magnames to thisspecification in the presence of 10 net which when broken establishes a.short two subscribing witnesses.

circuit through resistanee across the motor- WM. D. BALDWIN. 5 armature,another coil on said auxiliary mag- JOHN D. IHLDER.

net connected in the armature short circuit Witnesses:

and arranged to neutralize the effect of the THUS. M. LOGAN,

first coil. v ERNEST W. MARSHALL.

